Problem: In this problem your goal is to sort an array consisting of n integers in at most n swaps. For the given array find the sequence of swaps that makes the array sorted in the non-descending order. Swaps are performed consecutively, one after another.

Note that in this problem you do not have to minimize the number of swaps — your task is to find any sequence that is no longer than n.

Input

The first line of the input contains integer n (1 ≤ n ≤ 3000) — the number of array elements. The second line contains elements of array: a0, a1, ..., an - 1 ( - 109 ≤ ai ≤ 109), where ai is the i-th element of the array. The elements are numerated from 0 to n - 1 from left to right. Some integers may appear in the array more than once.

Output

In the first line print k (0 ≤ k ≤ n) — the number of swaps. Next k lines must contain the descriptions of the k swaps, one per line. Each swap should be printed as a pair of integers i, j (0 ≤ i, j ≤ n - 1), representing the swap of elements ai and aj. You can print indices in the pairs in any order. The swaps are performed in the order they appear in the output, from the first to the last. It is allowed to print i = j and swap the same pair of elements multiple times.

If there are multiple answers, print any of them. It is guaranteed that at least one answer exists.

Examples

Input

5
5 2 5 1 4


Output

2
0 3
4 2


Input

6
10 20 20 40 60 60


Output

0


Input

2
101 100


Output

1
0 1

Solution (in JAVA):

Solution:
		import java.io.BufferedReader;
		import java.io.IOException;
		import java.io.InputStream;
		import java.io.InputStreamReader;
		import java.io.OutputStream;
		import java.io.PrintWriter;
		import java.math.BigInteger;
		import java.util.ArrayList;
		import java.util.Arrays;
		import java.util.Collection;
		import java.util.Collections;
		import java.util.Comparator;
		import java.util.Deque;
		import java.util.HashMap;
		import java.util.HashSet;
		import java.util.Iterator;
		import java.util.LinkedHashMap;
		import java.util.LinkedList;
		import java.util.List;
		import java.util.Map;
		import java.util.PriorityQueue;
		import java.util.Queue;
		import java.util.Random;
		import java.util.Scanner;
		import java.util.Stack;
		import java.util.StringTokenizer;
		
		
		/**
		 * for competitive programming
		 * @author BrolyCode
		 * @version 1.0.0
		 */
		
		public class CP {
			static Random random;
			private static void mySort(int[] s) {
		        for (int i = 0; i < s.length; ++i) {
		            int j = random.nextInt(i + 1);
		            int t = s[i];
		            s[i] = s[j];
		            s[j] = t;
		        }
		        Arrays.sort(s);
		    }
			
			static class Pair{
				int x;
				int y;
				
				public Pair(int x, int y) {
					this.x=x;
					this.y=y;
				}
			}
			
			public static void sortPairX(Pair[] p) {
				Arrays.sort(p, new Comparator<Pair>() {
					public int compare(Pair o1, Pair o2) {
						return o1.x-o2.x;
					}			
				});
			}
			
			public static void sortPairY(Pair[] p) {
				Arrays.sort(p, new Comparator<Pair>() {
					public int compare(Pair o1, Pair o2) {
						return o1.y-o2.y;
					}			
				});
			}
			
			
		
			public static void main(String[] args) {
				random = new Random(543534151132L + System.currentTimeMillis());
				InputStream inputStream = System.in;
		        OutputStream outputStream = System.out;
		        InputReader in = new InputReader(inputStream);
		        PrintWriter out = new PrintWriter(outputStream);
		        
		        task(in,out);
		        
				out.close();
				
			}
		
			private static void task(InputReader in, PrintWriter out) {
				
				int n=in.nextInt();
				int[] A=new int[n];
				for(int i=0;i<n;i++)A[i]=in.nextInt();
				int[] B=Arrays.copyOf(A, n);
				mySort(B);
				
			    ArrayList<Pair> result=new ArrayList<Pair>();
				
				for(int i=0;i<n;i++) {
					if(A[i]==B[i])continue;
					else {
						for(int j=i;j<n;j++) {
							if(A[j]==B[i]) {
								result.add(new Pair(i,j));
								A[j]=A[i];
								A[i]=B[i];
								break;
							}
						}
					}
				}
				
				out.println(result.size());
				for(Pair p: result) {
					out.println(p.x+" "+p.y);
				}
				
			}	
			
			
		
			public static int gcd(int a, int b)  
		    { 
		        BigInteger b1 = BigInteger.valueOf(a); 
		        BigInteger b2 = BigInteger.valueOf(b); 
		        BigInteger gcd = b1.gcd(b2); 
		            return gcd.intValue(); 
		    } 
		      
		    public static long gcd(long a, long b)  
		    { 
		        BigInteger b1 = BigInteger.valueOf(a); 
		        BigInteger b2 = BigInteger.valueOf(b); 
		        BigInteger gcd = b1.gcd(b2); 
		            return gcd.longValue(); 
		    } 
			
			static class InputReader {
		        public BufferedReader reader;
		        public StringTokenizer tokenizer;
		
		        public InputReader(InputStream stream) {
		            reader = new BufferedReader(new InputStreamReader(stream), 32768);
		            tokenizer = null;
		        }
		
		        public String next() {
		            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
		                try {
		                    tokenizer = new StringTokenizer(reader.readLine());
		                } catch (IOException e) {
		                    throw new RuntimeException(e);
		                }
		            }
		            return tokenizer.nextToken();
		        }
		
		        public int nextInt() {
		            return Integer.parseInt(next());
		        }
		        
		        public long nextLong() {
		            return Long.parseLong(next());
		        }
		        
		        public double nextDouble() {
		            return Double.parseDouble(next());
		        }
		        
		        public float nextFloat() {
		            return Float.parseFloat(next());
		        }
		        
		    }
		
		}